[Mesa-dev] [PATCH 05/13] nir: expose 'C' wrappers for std430 size/alignment

[Karol Herbst]

On Wed, Feb 28, 2018 at 10:59 PM, Rob Clark <robdclark at gmail.com> wrote:
> hmm, I haven't tried passing a struct (rather than a pointer to a
> struct) as a parameter, but if there were 8/16 bit fields in the
> struct it would calculate the size incorrectly.
>
> (otoh the more important question is whether this agrees with how
> clover lays out the input buffer, as far as where the n+1'th parameter
> starts, which I'm not sure about)
>

you can also pack structs in OpenCL C. I just used those functions in
my backend code, because it worked for the more simple examples.

> BR,
> -R
>
> On Wed, Feb 28, 2018 at 4:47 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
>> I thought OpenCL used a different set of alignment rules for structs,
>> unions, etc.  In particular, I thought it was very close to standard C.  If
>> that's true, then std430 is not what you want.
>>
>> On Wed, Feb 28, 2018 at 1:44 PM, Karol Herbst <kherbst at redhat.com> wrote:
>>>
>>> it isn't yet. But you would use it in your driver when calculating
>>> your memory offsets for kernel arguments. In OpenCL things are aligned
>>> in memory by the size of the type and we would use those functions to
>>> calculate those.
>>>
>>> On Wed, Feb 28, 2018 at 10:39 PM, Jason Ekstrand <jason at jlekstrand.net>
>>> wrote:
>>> > Looking through commit titles, I don't see any obvious place where this
>>> > would get used.
>>> >
>>> > On Wed, Feb 28, 2018 at 11:51 AM, Rob Clark <robdclark at gmail.com> wrote:
>>> >>
>>> >> Signed-off-by: Rob Clark <robdclark at gmail.com>
>>> >> ---
>>> >>  src/compiler/nir_types.cpp | 12 ++++++++++++
>>> >>  src/compiler/nir_types.h   |  4 ++++
>>> >>  2 files changed, 16 insertions(+)
>>> >>
>>> >> diff --git a/src/compiler/nir_types.cpp b/src/compiler/nir_types.cpp
>>> >> index cbdd452dc81..0085a19248a 100644
>>> >> --- a/src/compiler/nir_types.cpp
>>> >> +++ b/src/compiler/nir_types.cpp
>>> >> @@ -117,6 +117,18 @@ glsl_get_aoa_size(const struct glsl_type *type)
>>> >>     return type->arrays_of_arrays_size();
>>> >>  }
>>> >>
>>> >> +unsigned
>>> >> +glsl_std430_size(const struct glsl_type *type, bool row_major)
>>> >> +{
>>> >> +   return type->std430_size(row_major);
>>> >> +}
>>> >> +
>>> >> +unsigned
>>> >> +glsl_std430_base_alignment(const struct glsl_type *type, bool
>>> >> row_major)
>>> >> +{
>>> >> +   return type->std430_base_alignment(row_major);
>>> >> +}
>>> >> +
>>> >>  unsigned
>>> >>  glsl_count_attribute_slots(const struct glsl_type *type,
>>> >>                             bool is_vertex_input)
>>> >> diff --git a/src/compiler/nir_types.h b/src/compiler/nir_types.h
>>> >> index e2dfd1ef5b7..5b5e09d137f 100644
>>> >> --- a/src/compiler/nir_types.h
>>> >> +++ b/src/compiler/nir_types.h
>>> >> @@ -71,6 +71,10 @@ unsigned glsl_get_length(const struct glsl_type
>>> >> *type);
>>> >>
>>> >>  unsigned glsl_get_aoa_size(const struct glsl_type *type);
>>> >>
>>> >> +unsigned glsl_std430_size(const struct glsl_type *type, bool
>>> >> row_major);
>>> >> +
>>> >> +unsigned glsl_std430_base_alignment(const struct glsl_type *type, bool
>>> >> row_major);
>>> >> +
>>> >>  unsigned glsl_count_attribute_slots(const struct glsl_type *type,
>>> >>                                      bool is_vertex_input);
>>> >>
>>> >> --
>>> >> 2.14.3
>>> >>
>>> >> _______________________________________________
>>> >> mesa-dev mailing list
>>> >> mesa-dev at lists.freedesktop.org
>>> >> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>>> >
>>> >
>>
>>